Inorganic Phosphate Glasses as Polymers

Joshua U. Otaigbe and George H. Beall

Abstract

It is now generally recognized that inorganic phosphate glasses are polymeric in nature in the sense that they are composed of chain-like structures like organic polymers. The chain-like structure of the former can range from 2 to 50 units of phosphate anion tetrahedra depending on the metal: phosphate ion ratio in the glass composition, but there is still some reluctance to accept the polymeric nature of other oxide glasses. This reluctance has resulted in researchers being mystified by several experimental observations such as shear-induced melt crystallization of such glasses. This article reviews some new insights into the melt crystallization mechanism, melt rheology and chain-like structure of phosphate glasses. The goal is to present new evidence and understanding showing that the structural dynamics of phosphate glasses are essentially similar to those observed in organic polymers. The unanswered questions are discussed to guide future research directions.